It may very well turn out that consciousness is dependent on engineering identical to a human brain in every respect, however we just don't know the answer to that yet.
By 'engineering' do you mean engineering of the 'data-processing' system itself without the downloading or uploading of informational data to the system? In other words, the production of an AI data processing system without data, yielding a kind of tabula rasa? Aren't AI engineers currently laying down data (about the world as they interpret it) at the same time as they are engineering the artificial processor? Wouldn't they have to do so to provide the AI with an informational basis from which to operate?
In either case I think there is bound to be an immense difference between the 'database' of any AI construction and the human brain since nature has engineered brains to evolve through the interactive experiences of individuals and species from primitive cells to ourselves in the physically evolving world.
How we contemporary humans variously conceive of the undefined term 'information' likewise seems to depend on how we variously conceive of 'reality', i.e., what is real. Tononi and Koch seem to have come back to a concept of reality long recognized by our species as the actual temporally changing world that we and other animals experience consciously and subconsciously. Nature has endowed us with an enormous store of information held subconsciously, by virtue of which we function much of the time. We do not yet know much about the subconscious mind and its influences on conscious experience and thus its contributions to mind as expressed in human thought. This is another major question impinging on the idea (I'm tempted to say 'notion') that we can engineer an artificial intelligence that possesses consciousness and mind remotely like our own.
Rightly or wrongly, IIT suggests that consciousness arises from information processed/organized/integrated in a particular manner.
The 'particular manner' is the question being begged. I think we have to take IIT as a work in progress and wait to see what ultimate form it takes in the thinking of Tononi, Koch, and their research group.